Eating disorders - Causes
It is not known with certainty what causes eating disorders. It can be due to a combination of biological, psychological or environmental causes. Biological (shown here in color), encircles the double helix to repair a broken strand of human DNA.]] * Genetic: Numerous studies have been undertaken that show a possible genetic predisposition toward eating disorders.The evolving genetics of eating disorders Psychiatric Clinics of North America 2001 Jun;24 (2):215-225 PMID 11416922Genetics in eating disorders:state of the science CNS Spectrum.2004 Jul;9(7):215-225 PMID 11416922Environmental and genetic factors for eating disorders: what the clinician needs to know Child and Adolescent Psychiatric Clinics of North America Jan;18(1):67-82 PMID 19014858 *Biochemical:Eating behavior is a complex process controlled by the neuroendocrine system of which the Hypothalamus-pituitary-adrenal-axis (HPA axis) is a major component. Dysregulation of the HPA-axis has been associated with eating disorders,Gross MJ Corticotropin-releasing factor and anorexia nervosa: reactions of the hypothalamus-pituitary-adrenal axis to neurotropic stressAnn Endocrinol (Paris). 1994;55(6):221-8. PMID 7864577Licinio J, Wong ML,The hypothalamic-pituitary-adrenal axis in anorexia nervosa. Gold PW.Psychiatry Res. 1996 Apr 16;62(1):75-83.PMID 8739117 such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormonesChaudhri O, Small C, Bloom S. Gastrointestinal hormones regulating appetite. Philos Trans R Soc Lond B Biol Sci. 2006 Jul 29;361(1471):1187-209. PMID 16815798 or neuropeptidesGendall KA.Leptin, neuropeptide Y, and peptide YY in long-term recovered eating disorder patients. Biol Psychiatry. 1999 Jul 15;46(2):292-9. PMID 10418705. **serotonin: a neurotransmitter involved in depression also has an inhibitory affect on eating behaviorJimerson DC, et.al.,Eating disorders and depression: is there a serotonin connection? Biol Psychiatry. 1990 Sep 1;28(5):443-54. PMID 2207221Leibowitz, The role of serotonin in eating disorders. Drugs 1990;39Suppl 3:33-44 PMID 2197074Blundell et al.''serotonin, eating behavior, fat intake Obes Res 1995 Nov;3 Suppl4:471s-476s PMID 8697045Kaye WH, Anorexia, obsessional behavior and serotonin, Psycopharmacology Bulletin 1997;33(3)335-44 PMID 9550876Bailer UF ''et al.''Altered 5-HT(2A) receptor binding after recovery from bulimia-type anorexia nervosa: relationships to harm avoidance and drive for thinness. Neuropsychopharmacology. 2004 Jun;29(6):1143-55. PMID 15054474 **norepinephrine is both a neurotransmitter and a hormone; abnormalities in either capacity may affect eating behaviorHainer V ''et al.,Serotonin and norepinephrine reuptake inhibition and eating behavior. Annals of The New York Academy of Sciences 2006 Nov;1083:252-69 PMID 17148744Altered norepinephrine in bulimia: effects of pharmacological challenge with isoproternol Psychiatric Residency 1990 Jul;33 (1):1PMID 2171006 **dopamine:which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of foodWang et, al. Brain dopamine and obesity Lancet 2001 Feb. 3;357(9253):354-357 PMID 11210998Volknow et al. ''Brain dopamine is associated with eating behavior in humans International Journal of Eating Disorder 2003 Mar:33 (2)136-42 PMID 1216579 *leptin and ghrelin; leptin is a hormone produced primarily by the fat cells in the body it has an inhibitory effect on appetite by inducing a feeling of saiety. Ghrelin is an appetite inducing hormone produced in the stomach and the upper portion of the small intestine. Circulating levels of both hormones are an important factor in weight control. While often associated with obesity both hormones and their respective effects have been implicated in the pathophysiology of anorexia nervosa and bulimia nervosa.Frederich R, Hu S, Raymond N, Pomeroy C. Leptin in anorexia nervosa and bulimia nervosa: importance of assay technique and method of interpretation. PMID 11919545 *immune system:studies have shown that a majority of patients with anorexia and bulimia nervosa have elevated levels of autoantibodies that affect hormones and neuropeptides that regulate appetite control and the stress response. There may be a direct correlation between autoantibody levels and associated psychological traits.Fetissov SO ''et al.''Autoantibodies against neuropeptides are associated with psychological traits in eating disorders. Proc Natl Acad Sci U S A. 2005 Oct 11;102(41):14865-70. Epub 2005 Sep 29.PMID 16195379Sinno MH.''et al. Regulation of feeding and anxiety by alpha-MSH reactive autoantibodies. Psychoneuroendocrinology. 2009 Jan;34(1):140-9. Epub 2008 Oct 8.PMID 18842346 *infection:PANDAS, is an abbreviation for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections. Children with PANDAS "have Obsessive Compulsive Disorder (OCD) and/or tic disorders such as Tourette's Syndrome, and in whom symptoms worsen following infections such as "Strep throat" and Scarlet Fever." (NIMH) There is a possibility that PANDAS may be a precipitating factor in the development of Anorexia nervosa in some cases, (PANDAS AN).Sokol MS. Child Adolesc Psychopharmacol. 2000 Summer;10(2):133-45.Infection-triggered anorexia nervosa in children: clinical description of four cases. PMID 10933123 *lesions:studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorderUher R, Treasure J. Brain lesions and eating disorders. J Neurol Neurosurg Psychiatry. 2005 Jun;76(6):852-7. PMID 15897510Houy E et al.''Anorexia nervosa associated with right frontal brain lesion. Int J Eat Disord. 2007 Dec;40(8):758-61. PMID 17683096Trummer M ''et al.,Right hemispheric frontal lesions as a cause for anorexia nervosa report of three cases Acta Neurochir (Wien). 2002 Aug;144(8):797-801; discussion 801. PMID 12181689 *tumors:tumors in various regions of the brain have been implicated in the development of abnormal eating patterns.Winston AP Pineal germinoma presenting as anorexia nervosa: Case report and review of the literature. Int J Eat Disord. 2006 Nov;39(7):606-8. PMID 17041920Chipkevitch E, Fernandes AC. Hypothalamic tumor associated with atypical forms of anorexia nervosa and diencephalic syndrome. Arq Neuropsiquiatr. 1993 Jun;51(2):270-4. PMID 8274094Rohrer TR et al.''Craniopharyngioma in a female adolescent presenting with symptoms of anorexia nervosa. Klin Padiatr. 2006 Mar-Apr;218(2):67-71. PMID 16506105Chipkevitch E. Brain tumors and anorexia nervosa syndrome. Brain Dev. 1994 May-Jun;16(3):175-9, discussion 180-2.PMID 7943600Lin L ''et al. Brain tumor presenting as anorexia nervosa in a 19-year-old man. J Formos Med Assoc. 2003 Oct;102(10):737-40. PMID 14691602 *brain calcification: a study highlights a case in which prior calcification of the right thalumus may have contributed to development of anorexia nervosa.Conrad R et al. Nature against nurture, calcification in the right thalamus in a young man with anorexia nervosa and obsessive compulsive personality-disorder CNS Spectrum 2008 Oct;13(10)906-10 PMID 18955946 *somatosensory homunculus; is the representation of the body located in the somatosensory cortex, first described by renowned neurosurgeon Wilder Penfield. The illustration was originally termed "Penfield's Homunculus", homunculus meaning little man. "In normal development this representation should adapt as the body goes through its pubertal growth spurt. However, in AN it is hypothesized that there is a lack of plasticity in this area, which may result in impairments of sensory processing and distortion of body image". (Bryan Lask, also proposed by VS Ramachandran) *Obstetric complications. There have been studies done which show maternal smoking, obstetric and perinatal complications such as maternal anemia, very pre-term birth (32Burke CJ, Tannenberg AE, Payton DJ Ischaemic cerebral injury, intrauterine growth retardation, and placental infarction. Dev Med Child Neurol. 1997 Nov;39(11):726-30.PMID 9393885Cnattinghuis S et.al. Very pre-term birth, birth trauma and the risk of anorexia nervosa among girls. Arch Gen Psychiatry 1999 Jul;56(7):634-8PMID 10401509Favoro A et al. Perinatal factors and the risk of developing anorexia nervosa and bulimia nervosa Arch Gen Psychiatry 2006 Jan;63(1)82-8. PMID 16389201Favoro A The relationship between obstetric complications and temperament in eating disorders:a mediation hypothesis Psychosom Med 2008 Apr.70(3):372-7 PMID 18256341Decker MJ et al.''Episodic neonatal hypoxia evokes executive dysfunction and regionally specific alterations in markers of dopamine signaling. Neuroscience. 2003;117(2):417-25. PMID 12614682Decker MJ, Rye DB.Neonatal intermittent hypoxia impairs dopamine signaling and executive functioning. Sleep Breath. 2002 Dec;6(4):205-10. PMID 12524574Scher MS.Fetal and neonatal neurologic case histories: assessment of brain disorders in the context of fetal-maternal-placental disease. Part 1: Fetal neurologic consultations in the context of antepartum events and prenatal brain development. J Child Neurol. 2003 Feb;18(2):85-92. PMID 12693773Scher MS, Wiznitzer M, Bangert BA.Cerebral infarctions in the fetus and neonate: maternal-placental-fetal considerations. Clin Perinatol. 2002 Dec;29(4):693-724, vi-vii. PMID 12516742Burke CJ, Tannenberg AEDev Med Child Neurol. 1995 Jun;37(6):555-62. Prenatal brain damage and placental infarction--an autopsy study. PMID 7789664Squier M, Keeling JW.The incidence of prenatal brain injury. Neuropathol Appl Neurobiol. 1991 Feb;17(1):29-38. PMID 2057048Al Mamun A et.''al. Does maternal smoking during pregnancy have a direct effect on future offspring obesity? Evidence from a prospective birth cohort study. Am J Epidemiol. 2006 Aug 15;164(4):317-25. PMID 16775040 Psychological Eating disorders are classified as Axis IWesten D, Harnden-Fischer J. Personality profiles in eating disorders: rethinking the distinction between axis I and axis II. Am J Psychiatry. 2001 Apr;158(4):547-62. PMID 11282688 disorders in the Diagnostic and Statistical Manual of Mental Health Disorders (DSM-IV). Published by The American Psychiatric Association. There are various other psychological issues that may factor into eating disorders, some fulfill the criteria for a separate Axis I diagnosis or a personality disorder which is coded Axis II and thus are considered comorbid to the diagnosed eating disorder. Axis II disorders are subtyped into 3 "clusters", A, B and C.The causality between personality disorders and eating disorders has yet to be fully established.Rosenvinge'' et al.'' The comorbidity of eating disorders and personality disorders: a metanalytic review of studies between 1983 and 1998 Eating and Weight Disorders 2000 June;5(2):52-61 PMID 10941603 Some people have a previous disorder which may increase their vulnerability to developing an eating disorder.Kaye WH Comorbidity of anxiety disorders with anorexia and bulimia nervosa. American journal of Psychiatry 2004 Dec;161(12)2215-21 PMID 15569892Thornton C, Russell J.Obsessive compulsive comorbidity in the dieting disorders Int J Eat Disord. 1997 Jan;21(1):83-7. PMID 8986521Vitousek K, Manke F. Personality variables and disorders in anorexia nervosa and bulimia nervosa. J Abnorm Psychol. 1994 Feb;103(1):137-47. PMID 8040475 Some develop them afterwards.Braun Dl Psychiatric comorbidity in patients with eating disorders. Psychological Medicine 1994;24:854-67 PMID 7892354 The severity and type of eating disorder symptoms have been shown to affect comorbidity.Spindler A, Milos G. Eat Behav. 2007 Aug;8(3):364-73. Links between eating disorder symptom severity and psychiatric comorbidity. PMID 17606234 The DSM-IV should not be used by laypersons to diagnose themselves, even when used by professionals there has been considerable controversy over the diagnostic criteria used for various diagnoses, including eating disorders. There has been controversy over various editions of the DSM including the latest edition DSM-V due in May 2013.Collier R. DSM revision surrounded by controversy. Media has become part of the cause for disorders such as anorexia and bulimia. Psychologists say since the media plays such a powerful role in US culture that it's escalating impressions on youth, beauty and weight have started to have negative effects on women that watch TV and are more exposed to the media. There is no direct evidence given that this is a new study, however, it has increasingly become part of popular media debate. CMAJ. 2009 Nov 17. PMID 19920166Kutchins H, Kirk SA.DSM-III-R: the conflict over new psychiatric diagnosesHealth Soc Work. 1989 May;14(2):91-101.PMID 2714710DSM-IV Diagnostic Criteria for Eating Disorders May Be Too Stringent Marlene Busko/ ArticleThe Politics of Disease Definition: A Summer of DSM-V Controversy in Review. Stanford Center for Law and the BiosciencesArticlePsychiatry manual's secrecy criticized. Los Angeles Times Article Personality traits There are various childhood personality traits associated with the development of eating disorders.Podar I, Hannus A, et.al.''Personality and affectivity characteristics associated with eating disorders: a comparison of eating disordered, weight-preoccupied, and normal samples .J Pers Assess. 1999 Aug;73(1):133-47.PMID 10497805 During adolescence these traits may become intensified due to a variety of physiological and cultural influences such as the hormonal changes associated with puberty, stress related to the approaching demands of maturity and socio-cultural influences and perceived expectations, especially in areas that concern body image. Many personality traits have a genetic component and are highly heritable. Maladaptive levels of certain traits may be acquired as a result of anoxic or traumatic brain injury, neurodegenerative diseases such as Parkinson's disease, neurotoxicity such as lead exposure, bacterial infection such as Lyme disease or viral infection such as Toxoplasma gondii as well as hormonal influences. While studies are still continuing via the use of various imaging techniques such as fMRI; these traits have been shown to originate in various regions of the brainGardini S ''et al.''Individual differences in personality traits reflect structural variance in specific brain regions. Brain Res Bull. 2009 Jun 30;79(5):265-70. Epub 2009 Mar 28. PMID 19480986 such as the amygdalaMarsh AA ''et al. Reduced amygdala response to fearful expressions in children and adolescents with callous-unemotional traits and disruptive behavior disorders. Am J Psychiatry. 2008 Jun;165(6):712-20. Epub 2008 Feb 15. PMID 18281412Iidaka T et al. Volume of left amygdala subregion predicted temperamental trait of harm avoidance in female young subjects. A voxel-based morphometry study. Brain Res. 2006 Dec 13;1125(1):85-93. Epub 2006 Nov 17. PMID 17113049 and the prefrontal cortexRubino V et al.''Activity in medial prefrontal cortex during cognitive evaluation of threatening stimuli as a function of personality style. Disorders in the prefrontal cortex and the executive functioning system have have been shown to affect eating behavior.Spinella M, Lyke J. Executive personality traits and eating behavior. Int J Neurosci. 2004 Jan;114(1):83-93. PMID 14660070Sinai C. et.''al.''Thyroid hormones and personality traits in attempted suicide. Psychoneuroendocrinology. 2009 Nov;34(10):1526-32. Epub 2009 Jun 13.PMID 19525070 Environmental Child maltreatment Child abuse which encompasses physical, psychological and sexual abuse, as well as neglect has been shown by innumerable studies to be a precipitating factor in a wide variety of psychiatric disorders including eating disorders. Children who are subjugated to abuse may develop a disordered eating pattern in an effort to gain some sense of control or for a sense of comfort. Or they may be in an environment where the diet is unhealthful or insufficient. Child abuse and neglect can cause profound changes in both the physiological structure and the neurochemistry of the developing brain. Children who as wards of the state were placed in orphanages or foster homes are especially susceptible to developing a disordered eating pattern. In a study done in New Zealand 25% of the study subjects in foster care exhibited an eating disorder. (Tarren-Sweeney M. 2006) An unstable home environment is detrimental to the emotional well-being of children, even in the absence of blatant abuse or neglect the stress of an unstable home can contribute to the development of an eating disorder.Horish N ''et al. Abnormal, psychosocial situations and eating disorders in adolescence. J.Am. Acad. Child Adolesc Psychiatry 1996 July;35(7) 921-7 PMID 8768353Kopp et al.''The fatal outcome of an individual with anorexia nervosa...OBJECTIVES:: To illustrate the close association between a disturbed psychosocial up-bringing, frequent physical illness, and medical interventions Int J Eat Disord. 2009 Feb 26;43(1):93-96. PMID 19247986Rayworth BB, Wise LA, Harlow BL. Childhood abuse and risk of eating disorders in women. Epidemiology. 2004 May;15(3):271-8. PMID 15097006 Wonderlich SA,''et, al., Relationship of childhood sexual abuse to eating disorders J. Am Acad Child Adolesc. Psychiatry Aug;36(8):110715 PMID 9256590Feldman MB, Meyer IH.Childhood abuse and eating disorders in gay and bisexual men. Int J Eat Disord. 2007 Jul;40(5):418-23. PMID 17506080Rohde P.et.al.''Associations of child sexual and physical abuse with obesity and depression in middle-aged women. Child Abuse Negl. 2008 Sep;32(9):878-87. Epub 2008 Oct 22. PMID 18945487Williamson DF.Body weight and obesity in adults and self-reported abuse in childhood. Int J Obes Relat Metab Disord. 2002 Aug;26(8):1075-82.PMID 12119573Waller G. Sexual abuse and the severity of bulimic symptoms. Br J Psychiatry. 1992 Jul;161:90-3. PMID 1638336Waller G, Halek C, Crisp AH. Sexual abuse as a factor in anorexia nervosa: evidence from two separate case series. J Psychosom Res. 1993 Dec;37(8):873-9. PMID 8301627 Social isolation Social isolation has been shown to have a deleterious effect on an individuals' physical and emotional well-being. Those that are socially isolated have a higher mortality rate in general as compared to individuals that have established social relationships. This effect on mortality is markedly increased in those with pre-existing medical or psychiatric conditions, this has been especially noted in cases of coronary heart disease. "The magnitude of risk associated with social isolation is comparable with that of cigarette smoking and other major biomedical and psychosocial risk factors." ( Brummett et al.) Social isolation can be inherently stressful, depressing and anxiety provoking. In an attempt to ameliorate these distressful feelings an individual may engage in emotional eating in which food serves as a source of comfort. The loneliness of social isolation and the inherent stressors thus associated have been implicated as triggering factors in binge eating as well.Troop NA, Bifulco A. Childhood social arena and cognitive sets in eating disorders. Br J Clin Psychol. 2002 Jun;41 (Pt 2):205-11. PMID 12034006Nonogaki K, Nozue K, Oka Y. Social isolation affects the development of obesity and type 2 diabetes in mice. Endocrinology. 2007 Oct;148(10):4658-66. Epub 2007 Jul 19. PMID 17640995Esplen MJ ''et al..Relationship between self-soothing, aloneness, and evocative memory in bulimia nervosa. Int J Eat Disord. 2000 Jan;27(1):96-100. PMID 10590454Larson R, Johnson C. Bulimia: disturbed patterns of solitude. Addict Behav. 1985;10(3):281-90. PMID 3866486 Parental influence Parental influence has been shown to be an intrinsic component in developing the eating behaviors of children. This influence is manifested and shaped by a variety of diverse factors such as familial genetic predisposition, dietary choices as dictated by cultural or ethnic preferences, the parents' own body shape and eating patterns, the degree of involvement and expectations of their children's eating behavior as well as the interpersonal relationship of parent and child. This is in addition to the general psychosocial climate of the home and the presence or absence of a nurturing stable environment. It has been shown that maladaptive parental behavior has an important role in the development of eating disorders. As to the more subtle aspects of parental influence it has been shown that eating patterns are established in early childhood and that children should be allowed to decide when their appetite is satisfied as early as the age of two. A direct link has been proven between obesity and parental pressure to eat more. Coercive tactics in regard to diet have not been proven to be efficacious in controlling a child's eating behavior. Affection and attention have been shown to affect the degree of a childs' finickiness and their acceptance of a more varied diet.Johnson JG,et al.''Childhood adversities associated with risk for eating disorders or weight problems during adolescence or early adulthood. Am J Psychiatry. 2002 Mar;159(3):394-400. PMID 11870002 Klesges RCJ Parental influences on children's eating behavior and relative weight. Appl Behav Anal. 1983 Winter;16(4):371-8.PMID 6654769 Galloway AT ''et al.''Parental pressure, dietary patterns, and weight status among girls who are "picky eaters".J Am Diet Assoc. 2005 Apr;105(4):541-8. PMID 15800554Jones C, Harris G, Leung N.Parental rearing behaviours and eating disorders: the moderating role of core beliefs. Eat Behav. 2005 Dec;6(4):355-64. Epub 2005 Jun 13. PMID 16257809Children's eating attitudes and behaviour: a study of the modelling and control theories of parental influence. Brown R, Ogden J. Health Educ Res. 2004 Jun;19(3):261-71. PMID 15140846Savage JS, Fisher JO, Birch LL. Parental influence on eating behavior: conception to adolescence. J Law Med Ethics. 2007 Spring;35(1):22-34. PMID 17341215 Peer pressure In various studies such as one conducted by The McKnight Investigators, peer pressure was shown to be a significant contributor to body image concerns and attitudes toward eating among subjects in their teens and early twenties. Eleanor Mackey and co-author, Annette M. La Greca of the University of Miami, studied 236 teen girls from public high schools in southeast Florida. "Teen girls' concerns about their own weight, about how they appear to others and their perceptions that their peers want them to be thin are significantly related to weight-control behavior," says psychologist Eleanor Mackey of the Children's National Medical Center in Washington and lead author of the study. "Those are really important." Dieting among adolescents was also reported to being influenced by peer behavior. With many of those individuals on a diet reporting that their friends also were dieting. The number of friends dieting and the number of friends who pressured them to diet also played a significant role in their own choices.Page RM, Suwanteerangkul J.Dieting among Thai adolescents: having friends who diet and pressure to diet. Eat Weight Disord. 2007 Sep;12(3):114-24. PMID 17984635 The McKnight Investigators. Risk factors for the onset of eating disorders in adolescent girls: results of the McKnight longitudinal risk factor study. Am J Psychiatry. 2003 Feb;160(2):248-54.PMID 12562570 Paxton SJ ''et, al. Friendship clique and peer influences on body image concerns, dietary restraint, extreme weight-loss behaviors, and binge eating in adolescent girls. J Abnorm Psychol. 1999 May;108(2):255-66. PMID 10369035Rukavina T, Pokrajac-Bulian A. Eat Weight Disord. 2006 Mar;11(1):31-7. Thin-ideal internalization, body dissatisfaction and symptoms of eating disorders in Croatian adolescent girls. PMID 16801743 Cultural pressure There is a cultural emphasis on thinness which is especially pervasive in western society. There is an unrealistic stereotype of what constitutes beauty and the ideal body type as portrayed by the media, fashion and entertainment industries."The cultural pressure on women to be thin is an important predisposing factor for the development of eating disorders" (Bryan Lask, PhD) Garner DM, Garfinkel PE.Socio-cultural factors in the development of anorexia nervosa. Psychol Med. 1980 Nov;10(4):647-56. PMID 7208724 Eisenberg ME, Neumark-Sztainer D, Story M, Perry C.The role of social norms and friends' influences on unhealthy weight-control behaviors among adolescent girls. Soc Sci Med. 2005 Mar;60(6):1165-73. PMID 15626514 Eating disorders in men There has been an increasing rate of males suffering from various eating disorders including anorexia nervosa. There is a perceived stigma attached, as eating disorders are generally viewed as primarily affecting women. Among men the rates of eating disorders are higher in the gay and bi-sexual communities (Feldman & Meyer, 2007), yet it also affects heterosexual men. Despite the perceived stigma, some high profile male celebrities have publicised their struggles with eating disorders such as actor Dennis Quaid, who struggled with what he called "manorexia" for which he sought treatment. Quaid said his problems began when he went on a diet to lose forty pounds to play Doc Holliday in the movie "Wyatt Earp" in 1994. Billy Bob Thornton has also struggled with anorexia, once losing 59 lbs.Thomas Holbrook, M.D., is Clinical Director of the Eating Disorders Program at Rogers Memorial Hospital in Oconomowoc, Wisconsin despite being a psychiatrist specializing in eating disorders, he suffered from anorexia nervosa with compulsive exercising. At one time the 6-ft.-tall psychiatrist weighed just 135 lbs. "I was terrified," he says, "of being fat." His story has been chronicled in various publications including USA Today and People Magazine. References Category:Causes of mental disorders category:Eating disorders